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to add 2 very long integers

P: n/a
hi
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.

Apr 19 '06 #1
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P: n/a
vicky_in wrote:
hi
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.


Your platform might support built-in or extenstions for integers of
sufficicent size (e.g., long, long long, __int64, __int128, etc.) for
your needs, you could use a floating point representation if the least
significant digits aren't important, or you could use a third-party big
int library that allows for integers of arbitrary length (cf.
http://www.parashift.com/c++-faq-lit...html#faq-37.9).

Cheers! --M

Apr 19 '06 #2

P: n/a
vicky_in wrote:
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.


Google "bigint". That's the common name for a class library that manages
arbitrary-size integers.

The answer to the actual question is to express the integer as an array of
ints, where each element is a "place" in counting theory, just like
elementary school arithmetic. Except instead of a 10s place, you have a ~2
billions place. Then to add you detect overflows, and carry to the next
place.

--
Phlip
http://www.greencheese.org/ZeekLand <-- NOT a blog!!!
Apr 19 '06 #3

P: n/a
"vicky_in" writes:
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.


If it is a practical problem, there are several libraries that handle big
integers. Lists of libraries are posted occasionally to this group and/or
comp.language.c. You could find a recent list using Google groups.

If it is learning thing, the easiest way is probably to write a BCD adder,
since it minimizes the conversion to/from binary problems.
Apr 19 '06 #4

P: n/a
"vicky_in" <vi************@gmail.com> skrev i meddelandet
news:11**********************@i39g2000cwa.googlegr oups.com...
hi
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.


Hi,

You have two options;

1) Program basic addition between two natural numbers (of arbitrary size).
I guess you know how.

2) Use a third party library that performs the above mentioned addition.

Regards,
Peter Jansson
Apr 19 '06 #5

P: n/a
vicky_in wrote:
hi
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.


http://www.swox.com/gmp/

--
Paul M. Dubuc
Apr 19 '06 #6

P: n/a
In message <11**********************@i39g2000cwa.googlegroups .com>,
vicky_in <vi************@gmail.com> writes
hi
is anyone tell me any idea about to add 2 integers having more than
20 digits.
e.g. 125865235989523352897956+565896589795623968955632.

How would you do it with paper and pencil?

If you write down the rules for that, you are half way to designing a
program that will do it for you.

--
Richard Herring
Apr 19 '06 #7

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